Dynamics of Polyhedral Oligomeric Silsesquioxane (POSS) Polymer Nanocomposites

Dynamic behavior of POSS/polymer nanocomposites is studied by dielectric and viscoelastic relaxation. Our goal here is to identify the various relaxation processes in nanosystems, establish their origin and seek the relationship between dielectric and viscoelastic response. Studies of dynamics probe the motions of molecules in applied fields, such as electric or mechanical, and are crucial for understanding processing and properties of materials.

Consider example of multifunctional POSS/PPO blends. Fig. 2 shows how segmental and normal mode processes shift to higher frequency with increasing POSS concentration. Preliminary observations suggest that POSS promotes the motion of the PPO chains. Fig. 3 shows the combined effects of POSS concentration (5-30 wt%) and PPO molecular weight (2-8 kDa) on the blend morphology. Further investigation is currently underway.

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POSS Polypropylene oxide (PPO) POSS/PPO Blend

Fig. 1

Fig. 1 Formation of POSS/PPO blend.Fig. 2 Dielectric loss in the frequency domain for POSS/PPO blends with different concentration (from 9 to 45wt%) .Fig. 3 Micrographs of POSS/PPO blends with different POSS concentration (5-30 wt%) and PPO molecular weight (2-8 kDa)

Jovan Mijovic and Yu Bian (Polytechnic University)

and Jose Kenny (University of Perugia, Italy) DMR-0346435 NSF-EC

(a) PPO2k with 17wt% POSS (b) PPO2k with 30wt% POSS (d) PPO8k with 30wt% POSS(c) PPO8k with 5wt% POSS

Fig. 3

Dynamics of Nanostructured Systems Jovan Mijovic, Polytechnic University, DMR-0346435 NSF-

ECEducation:Four Chemical Engineering PhD students: HyungKi Lee (3nd year), Yu Bian (3nd year), Sanja Ristic (2st year), Chetan Khamar (1st year) and four undergraduate students in Chemical and Biological Engineering: Ruel McKenzie (Senior), Anastasija Shytuhina (Junior), Darya Kozlova (Senior) and Qi Ke Chen (Junior) are currently involved in this program.

Outreach:Every year our lab accommodates a number of under-represented minority students from New York City high schools under the aegis of the YES (Youth in Engineering and Science) summer program at Polytechnic University.

Photo Caption:From left to right: Sanja Ristic, Ruel McKenzie, Yu Bian, HyungKi Lee, Anastasija Shytuhina, Professor Mijovic, Darya Kozlova and Qi Ke Chen. Chetan Khamar is not in the picture.